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X-Ray Diffraction Analysis and Magnetic Properties of Pr-Fe-B HDDR Powders and Magnets

Journal Materials Science Forum (Volumes 591 - 593)
Volume Advanced Powder Technology VI
Edited by Lucio Salgado and Francisco Ambrozio Filho
Pages 42-47
DOI 10.4028/www.scientific.net/MSF.591-593.42
Online since August, 2008
Authors S.C. Silva, J.H. Duvaizem, L.G. Martinez, M.T.D. Orlando, R.N. Faria, H. Takiishi
Keywords HDDR Powder, Pr-Fe-B Magnet, X-Ray Diffraction Analysis
Abstract Fine magnetic powder has been produced using the hydrogenation disproportionation desorption and recombination (HDDR) process. The first goal of this work involved an investigation of a range of disproportionation/desorption temperatures between 800 and 900°C with the purpose of optimizing the HDDR treatment for a Pr14Fe80B6 alloy. The cast alloy was annealed at 1100°C for 20 hours for homogenization. The optimum disproportionation temperature for achieving high anisotropy was 820°C. The influence of the reaction temperature on the microstructure and magnetic properties of Pr14Fe80B6 HDDR powders and magnets has been shown. A second stage of this study involved the characterization, for each temperature, of the HDDR processed powder using X-ray diffraction analysis. Samples of the HDDR material have been studied by synchrotron radiation powder diffraction using the Rietveld method for cell refinement, phase quantification and crystallite sizes determination. Scanning electron microscopy (SEM) has also been employed to reveal the morphology of the HDDR powder.
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